I thought it was interesting that only 5 teams of the 14 teams that made last year's playoffs won their week 1 games.
AFC
1. Tennessee Titans (12-5) — LOST
2. Kansas City Chiefs (12-5) — **WON
3. Buffalo Bills (11-6) — **WON
4. Cincinnati Bengals (10-7) — LOST
5. Las Vegas Raiders (10-7) — LOST
6. New England Patriots (10-7) — LOST
7. Pittsburgh Steelers (9-7-1) — **WON
NFC
1. Green Bay Packers (13-4) — LOST
2. Tampa Bay Buccaneers (13-4) — **WON
3. Dallas Cowboys (12-5) — LOST
4. Los Angeles Rams (12-5) — LOST
5. Arizona Cardinals (11-6) — LOST
6. San Francisco 49ers (10-7) — LOST
7. Philadelphia Eagles (9-8) — WON
Additionally, 4 teams that won were playing other 2021 playoff teams, which means 4 of the 5 playoff teams who won were playing in a game that was guaranteed a win to a playoff team.
In other words, the minimum possible 2021 playoff team wins for week 1 was 4 teams and only 5 actually won.
My point in posting this is not really related to the Cowboys, but rather to point out that judging how good a team is and how hard a schedule is before the season starts and the first few weeks of games are played is not really valid.